The influence of Fosetyl-Al and Metalaxyl on the diversity of arbuscular
mycorrhizal fungi (AMF) was evaluated on naturally
established citrus plants. Thirteen AMF species were recovered from rhizospheres
of
Citrus sinensis/C. limon treated or not with
Fosetyl-Al and/or Metalaxyl. Spores of AMF were obtained from 100 g
of
rhizospheric soil at two sites in São Paulo state, Brazil.
The soil samples were treated by the wet-sieving technique and the spores
were quantified and identified. The number of spores was
low at both sites. Fosetyl-Al reduced the number of spores and the diversity
of AMF in one site but not in the other. Metalaxyl at
low concentration increased the diversity of species in some experiments,
but
at higher concentration it tended to reduce the number
of spores of AMF. Scutellospora was the genus that presented the
largest
number of species (7) followed by Acaulospora (3), Glomus
(2) and Gigaspora (1). Gigaspora ramisporophora was the
dominant
species in one site, Glomus macrocarpum and Scutellospora
gilmorei
were dominant at the other.